Lubricants



Patented Aug. i945 ilifi S"? LUBRKCAN TS No Drawing. Application .liul'y 3, 3942, Serial Ne. 449,5h9

5 @las.

This invention relates to low temperature lubricants. More particularly the invention relates to lubricants which have a comparatively uniform viscosity over a wide temperature range.

Some pieces of mechanism such as the aeroplane, motor vehicle, guns and superstructures of ships, are subject to a wide range of temperatures in their normal operations. The aeroplane encounters this wide temperature range by operation in different altitudes while the motor vehicle, ships, guns and the like are subjected to changes in temperature in accordance with the seasons or in accordance with the particular lo- Boiling Flash Freezing point point point 5 Monomethyi ether of diethyleue gly- F. F. F.

col 380 200 75 Monoethyl ether diethylene glycol. 396 210 -l Monobutyl ether 0! diethylene glycoL 448 1 230 -60 Diethyl ether of diethylene glycol. 367 180 cation on the earths surface where the opera tions may take place.

It is important that lubricants for some types of mechanism should have'good lubricating characteristics, such as low viscosity, throughout the entire temperature range in which it is operated. It is also important that the lubricant shall have a proper boiling point, melting point and vapor pressure in order to function properly throughout a wide temperature range.

Many difierent metals and alloys are now used for bearings and it is important that the lubricants shall not be corrosive. Also good lubricants should be capable of standing high bearing pressures.

The primary object or the present invention is to provide a lubricant which will efiectively lu- I bricate at subzero temperatures as well as at high temperatures.

Another object of the invention is to provide a lubricant having comparatively uniform viscosity over a wide range of temperatures and which is adaptable for high bearing pressures.

A further object of the invention is to provide a lubricant which is not corrosive and which is stable while operating over a wide temperature range. I I With these and other objects in view the invention consists in the improved lubricant hereinafter described and particularly defined in the claims.

The preferred lubricant of the present invention consists of synthetic chemical compounds which are manufactured and sold to the trade under the trade-mark Carbitols. There are four Carbitols which have desirable characteristics as lubricants, namely, monomethyl ether of diethylene glycol; monoethyl ether of diethylene glycol; monobutyl ether of diethylene glycol; and diethyl ether of diethylene glycol. These Carbitols have the following physical characteristics:

All oi these Carbitols have oiliness or lubricating characteristics and when from 1% to 5% of the Carbitols are dissolved in a mineral lubricating oil they will raise the load-carrying characteristics of the mineral oil to give it ability to stand high bearing pressures. It is desirable, however, to use the Carbitols as the base lubricants by adding to the Carbitols extreme pressure additives, such as tricresyl phosphite, Polane, or Santolube No. 261, to increase the oiliness and load-carrying characteristics of the Carbitols. About 1% by volume of these additives will impart sufiicient load-carrying characteristics to the Carbitols for most lubricating purposes.

The Carbitols all have low freezing points and show comparatively uniform viscosities over a wide range of temperature. The viscosities of some of the Carbitols have been determined as follows:

The monomethyl ether of diethylene g ycol and the monobutyl ether of diethylene glycol (preferably with an additive agent therein) are well adapted as the base lubricant for the manufacture of low temperature greases. For example, sodium base greases may be made by dissolving from 4% to 20% of sodium base soaps in the monobutyl or monomethyl Carbitols. The sodium base soaps may be sodium stearate, sodium oleate, or sodium palmitate. To these greases may be added 1% of Polane, or 1% of tricresyl phosphite, or 1% of Santolube #261.

Among the extreme pressure additives which may be added to the glycols to increase their 1oad carrying capacities are Polane, a commercial product on the market sold by the Patent Chemicals Company which is understood to be an ester of a fatty acid or a chlorinated ester of a fatty acid, such as ethyl laurate, or chlormethyl stearate. Another additive is Santolube #261 which is manufactured by the Monsanto Chemical Company. This product is defined as a metallic derivative of an alkylated carboxylic acid containing compounds of tin and sulfur. The tricresyl phosphite, referred to above, is described in the patent to Engelke No. 2,260,303 granted October 28, 1941 as a tricresyl phosphite or a mixture of tricresyl phosphite and tricresyl phosphate. All of the above additives act as anticorrosion agents as well as extreme pressure and been thus described, what is claimed as new is:

1. A lubricant consisting of from approximately 96% to 80% of a diethyiene glycol monoalkyl ether, and from approximately 4% to 20% or a sodium soap.

2. A lubricant consisting of from approximately 4% to 20% of a sodium soap, approximately 1% of an extreme pressure agent, the remainder of the lubricant consisting essentially of a diethylene glycol monoalkyl ether.

3. A lubricant consisting of from approximately 96% to 80% of a diethylene glycol monoethyl ether, and from approximately 4% to 20% of a sodium soap.

4. A lubricant consisting of from approximate- 1y 96% to 80% of a diethylene glycol monoethyl ether, and from approximately 4% to 20% of a sodium soap.

5. A lubricant consisting of from approximately 96% to 80% of a diethylene glycol monobutyl ether, and from approximately 4% to 20% of a sodium soap.

JOHN D. MORGAN. 

